In recent years, with the rapid development of the internet technology and e-business, more and more business activities turn to internet, for example, online office, digital bank, online shopping etc. At the same time, more and more information associated with privacy and business secrets need to be transferred over internet. However, malicious threats such as virus, hacker, and online transaction and phishing fraud compromise the security of online transactions seriously.
The information security device is a small hardware appliance with processor and memory and in connection with a computer through its data communication interface. The device has functions such as creation of a key, secure storage of the key, predetermination of encryption algorithm. The information security device makes key-related operation inside itself with the anti-attack feature, therefore it is safer. Generally, the information security device is in connection with the host through USB (Universal Serial Bus) interface, so it is usually called USB KEY or USB Token. The information security device manufacturer, software system vendor or end user can store some important information into the information security device in order to ensure the security or prevent it from being neglected. At present, the relatively high-end information security device is programmable, this means that, the device can run those codes pre-stored in it.
A conventional information security device has a built-in security design chip to ensure information security. Besides for those features owned by universal embedded micro-controller, the security design chip has more advantages on security. The chip makes some special arrangements on its structure in aspect of security. For example, the chip uses a specific security kernel, which supports multiple states with different privilege definition, to manage the access privileges of hardware resources. The kernel also supports randomization of instruction cycle, and its interruption system can finish the conversion of chip state and thereby control the security level of different layers in order to support the realization of the multi-application. Further, the kernel may has a MMU (Memory Management Unit) used to separate logic address from the physical address, and to set up address mapping. As a result, the MMU supports the design realization of multi-application, security and organically forms a hardware firewall along with different states supported by the kernel. The interruption system of the kernel can support the transfer and switch of the interface and privilege between the system database and client program. The kernel can use the non-volatile storage media as well. Generally speaking, the security design chip will be required to be complied with relative standards, and to pass the corresponding validations, in order to ensure its security, such as TCG TPM v1.2 specification, ISO 15408 international standard, standard of the State Password Administration Committee of China etc. At present, there are various security chips to choose, among which the ST19WP 8 micro-controller of ST Semiconductor has acquired the Common Criteria EAL5+ certificate, it is the highest standard of this type of products with ISO 15408 standard.
The conventional information security device has built-in security design chips to ensure the information security. Since the integrated circuit technique is applied to the information security field, the information security has got ensured further. The chip specially used to information security protection, based on the integrated circuit technology, is called security design chip. The chip processes the protected information by the following three methods: firstly, implement the information processing algorithm(s) with hardware completely (logic encryption); secondly, implement the information processing algorithm(s) with software (intelligence) completely; thirdly, implement the information processing algorithm(s) by combining software and hardware (programmable logic encryption). At present, the most widely-used hard disk interface in computer system is the IDE (Integrated Drive Electronics) interface, shortened as IDE interface. The IDE interface, or more accurately, the ATA (Advanced Technology Attachment) interface, uses a parallel interface mechanism and is also called the parallel ATA interface. This interface technology originated in 1986 and formed a standard in 1988, which provides a specification for attaching the disk to a personal computer. In recent years, in order to meet the requirement of higher access speed of a processing unit to drive data, with the constant development of ATA interface technology, various standards have been set up, such as ATA/ATAPI, EIDE, ATA-2, high-speed ATA, ATA-3, Ultra ATA, Ultra DMA, ATA/ATAPI-4, ATA/ATAPI-5, ATA/ATAPI-6 etc. Now the parallel ATA interface is in dominant position between hard disks inside a desktop and a notebook PC due to its simplicity and low cost. However, the parallel ATA has many disadvantages, making people so boring on continuous improving its performance. Those disadvantages include: numerous pins, cables with 40 pins and 80 chips along with short in lengthen, inconvenient hard disk access, unable to meet the cooling requirement of a system. Along with other features of parallel ATA interface, which all together contribute to the slow development of data transfer rate of the interface in the past. As a result, the parallel ATA is already close to its designed maximum data transfer rate, unable to meet the further requirement of computer data transfer rate.
In consideration of those above-mentioned disadvantages, in order to meet the requirement of developing the next-generation interface technology, the serial ATA interface becomes the next-generation ATA standard. SATA (Serial Advanced Technology Attachment) interface technology, namely Serial ATA, is a new technology in storage field being developed in recent years. Serial ATA packs bits of data with serial structure, and then transfers them to the host in group with higher speed than parallel ATA.
SATA interface can provide the following advantages:
1. High-Speed
Few of the present parallel ATA interface can reach the maximum bandwidth of data line. Even the ATA/133 hard disk can not reach the transfer rate of 133 MB/S actually, just with stable transfer rate of 60 MB/S at most, while the serial ATA can reach the highest transfer rate of 600 MB/S.
2. Point-to-Point Communication
The serial ATA uses the point-to-point transfer protocol, so the master/slave problem does not exist. In this case each driver can not only use independent bandwidth, but also achieve more convenience in extending ATA device. As a result, users will be no longer worried about configuration of master/slave jumpers. They just need to increase the number of channels, devices will be connected together.
3. Hot Plug Support
SATA supports hot plug, the same as USB and IEEE 1394, which can add or remove a hard disk when power is still on without damaging the hard disk and controller.
4. Built-in Data Check
SATA uses brand-new CRC (Cyclic Redundancy Check) protection systems in both ends of the transfer bus. The bidirectional CRC of SATA seems less useful for common home, but extremely important for high-end workstations and servers.
SATA interface, developed from parallel ATA interface, has less pins, softer cables, longer access cables for hard disks than those of parallel ATA, convenient for hard disks to access a host, along with hot-plug support. Additionally, less pins in SATA interface benefit system design of main boards comprising chips and other integrated semiconductor parts, making them easy to put outside and move, which meets the demand on developing the next-generation interface technology.
In the aspect of removable storage, eSATA (External Serial ATA) technology emerges, which means that, the SATA interface is transferred from inside the main board to outside of the chassis. The eSATA, as an external extension standard of SATA interface, has significant advantages. Comparing with two conventional external interfaces of USB2.0 and IEEE1394, eSATA boasts of excellent data transfer capability. The transfer rate of eSATA can reach 300 MB/s, far higher than 480 Mbp/s of USB2.0 and 400 Mbp/s of IEEE1394. Moreover, eSATA still supports hot-plug, this means that, users can configure or remove SATA device without shutting down the computer. With the emergence of eSATA, the transfer rate of an external interface exceeds far from the internal rate of devices such as hard disks for the first time. Recently, storage device manufacturers comprising Seagate turn its main businesses to external hard disks. At CES2006, Seagate debuts its keyboard back-up series of external hard disks, among which the interface speed of 500 GB ones is up to 300 MB/s. Meanwhile, companies, such as Data-Tec, I-O DATA, launched their own eSATA external hard disks or DVD burners in succession, while there are the main boards with eSATA interface emerged on sale, like 775XFire-eSATA2 of HUA QING and P5W DH of ASUS etc. Besides that, Seagate has designed and produced eSATA external hard disks.
At present, the widely used USB Key has the following disadvantages:
1. Because the highest transfer rate of the present USB can only reach 10 MB/S, the transfer rate is limited greatly.
2. USB technology, based on a master/slave transfer protocol, may occupy more CPU resources compared with the point-to-point transfer protocol.